Laura, I agree with Holly that you just need to take a deep breath and quit looking for the perfect answer!
Next, all the stuff she said about the various suggestions you had mentioned are pretty much 'on the money'. I have friends who are pharmacists (one of the areas Holly wasn't familiar with) and they enjoy it. They both are mothers, work part time, and pretty much pick their hours (or just change pharmacies if they get too many hours or the wrong shifts. They are a pretty hot commodity).
One thing I would start by saying is that getting a college degree is a GEAT idea so that you have something to fall back on once you start your family and the children start school. You will have a better idea of what you REALLY want to do, once you become a mother and you are ready to go back to work.
Once you have your family and are ready to start working, it is usually much easier to quickly pick up a few additional courses you might need after you have your degree. You can always get those courses online while the children are still babies.
Something that you can do part-time, when YOU choose your own hours, is probably the best thing for a young woman planning to start a family. (Obviously something that pays pretty well to make up the difference for being part-time). Some of your ideas could make excellent transitions into an "Independent Consultant", like LOCATING a catering service for an out of state event planner, rather than working FOR the catering service).
Travel agent is another job I think that you could do at home, as an independent consultant, but you would need to take college courses to learn how to advertise and market yourself!
I agree that some careers are better as 2nd jobs or hobbies. The most important thing, IN MY OPINION, is to really contemplate what it is that you LOVE to do and enjoy so much that you would not consider it work!
The best career in the world in one that you don't think of as a "job", because you have so much fun, satisfaction, creativity, independence, and receive so much respect and enjoyment. It's like YOU get paid for doing something that you "LOVE" to do anyway. It becomes a win-win situation.
So my biggest advice, Laura, is to think about things that you really love to do, make a list of each thing that would be good and bad about it as a new parent, and decide which you think would be the most FUN! Remember,
all of us have made career changes and you can, too! So don't be afraid to choose a career and go after it, because once you have children and they grow up, you might change your mind again.
Life is wondorously and hopefully long, and education is GREAT, so follow your passion, enjoy and GOOD LUCK!